Small multiples: the fix for the chart with too many lines
The spaghetti chart — twelve lines in twelve colours with a legend down the side — is one of the most common failures in reporting. The fix is not a better palette, it is more charts.
Repetition beats overlay
Small multiples give each series its own miniature chart in a grid. Because every panel is identical in shape and scale, the eye compares them the way it compares words on a page — fast, and without a legend.
The axes must be shared
This is the rule people break. If each panel scales to its own maximum, a tiny series looks identical to a huge one and the grid becomes actively misleading. One scale for all panels, always.
Sort the panels by something meaningful
Alphabetical order wastes the layout. Sorting by size, by growth or by how much they deviate from the average turns the grid itself into a ranking.
Keep each panel almost bare
A title, the line, and axis labels only on the edges of the grid. Repeating gridlines and tick labels twelve times is what makes small multiples feel cluttered.
Split your series →A useful hybrid: one panel per series, with a faint grey copy of all the other series behind each one, so every panel carries its own context.
Frequently asked
How many series is too many for one line chart?
About five. Beyond that, colours stop being distinguishable and the legend does more work than the chart.
Do small multiples need the same axis scale?
Yes. Independent scales make small values look like large ones, which defeats the entire purpose of putting the panels side by side.